Venous disorders as an occupational disease - a systematic review on epidemiology, pathophysiology, and modification strategies.

Forced postures are common in the workplace. Work in the primary economic sector is characterised by a high degree of physical activity and movement; however, activities in the secondary and tertiary sectors commonly require workers to stand or sit. An expansion of the tertiary sector in recent decades has meant that people in industrialised and emerging economies primarily sit or stand at work. The aim of the systematic review was to identify occupational factors relating to the presence of chronic venous disease (CVD), to place these in the context of developments in the workplace, and to determine whether measures are in place to prevent CVD. We performed a systematic literature review to analyse studies assessing work-related risk factors for CVD. We searched for publications in the PubMed database, the clinic library of BG Hospital Bergmannstrost Halle, and the registry of the German Statutory Accident Insurance. Using occupation-specific keyword combinations, we identified 27,522 publications. The publications underwent an automatic and manual filtering process according to the PRISMA guidelines and 81 publications qualified for the review. Ultimately 25 studies were included in the systematic review. All of the subjects of the studies worked in the secondary and tertiary sectors. No studies looked at the relationship between venous disorders and primary sector occupations. Standing at work for more than four hours a day, repeated heavy lifting, and cumulative time working in a sitting or standing position are risk factors for the development of CVD. Sitting is less of a risk factor than standing or walking. Occupational history and the patient's activity profile are important diagnostic tools which can help confirm a diagnosis and justify treatment when findings are inconsistent. Compression therapy is the primary form of secondary and tertiary prevention. There continues to be a lack of primary preventive measures related to workplace design.

[Correlation analysis of cervical spine dysfunction, pain and muscle strength in office workers].

Objective: To expore the correlation between neck disability, neck pain and muscle strength in cervical pondylosis of office worker, and to provide scientific basis for the prevention and treatment of cervical spondylosis. Methods: In April 2021 ,234 patients with cervical spondylotic myelopathy treated in the Subsidiary Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine from April 2015 to April 2017 were selected, the correlation between Neck Disability Index (NDI) score, neck pain and muscle strength was analyzed using the Spearman rank correlation method. Mann-Whitney U test was used to compare the difference of maximum muscle strength of isometric contraction. Results: NDI score was negatively correlated with neck flexion, extension, and muscle strength in the left and right flexion directions (r(s)=-0.164, -0.169, -0.222, -0.176, P=0.012, 0.010, 0.001 , 0.007). In mild and moderate functional disorder patients, the muscle strength in flexion, extension and left and right flexion direction was greater, the difference was statistically significant (P <0.01). Conclusion: There is a negative correlation between cervical functional disorder and cervical muscle strength in office workers, suggesting that strengthening cervical muscle strength may be a way to improve cervical spine function.

Assessing cardiovascular links to depression and anxiety in Australian professional drivers.

Train and truck drivers experience a myriad of unique occupational factors, which have been postulated to contribute to a high incidence of health conditions such as depression anxiety and cardiovascular disease amongst this population. The present study aimed to identify associations between heart rate variability and negative mood states such as depression and anxiety in a cohort of Australian truck and train drivers. 120 professional drivers (60 truck drivers, 60 train drivers) were recruited from the local community. Participants complete a battery of psychometric questionnaires to assess levels of negative mood states such as depression and anxiety. Participants then completed a baseline (resting) and active (driving) task while concurrent electrocardiography data was collected to obtain heart rate variability parameters. Anxiety and depression were found to be associated with increases in low frequency heart rate variability and sympathovagal balance, and a reduction in total power. The present study identified associations between negative mood states and heart rate variability parameters that are unique to this cohort.

Correlations between body postures and musculoskeletal pain in guitar players.

BACKGROUND: The guitar-playing community is the largest group at risk of developing playing related musculoskeletal disorders. A thorough investigation of the relationships between the various risk factors and players' report on musculoskeletal pain using objective and accurate means of assessment has yet to be reported. PURPOSE: (a) to explore the correlations between demographic characteristics, anthropometric measurements, playing habits, and personal habits of guitar player and their complaints of musculoskeletal pain, (b) explore the correlations between the upper body kinematics of guitar players during playing the guitar and their complaints of musculoskeletal pain, and (c) compare the upper body kinematics of guitar players during playing the guitar while sitting versus standing. METHODS: Twenty-five guitar players (27.5±4.6 years old) filled out questionnaires regarding their guitar-playing habits, and the Standardized Nordic Questionnaires for the analysis of musculoskeletal symptoms. Kinematics of their torso and upper limbs were tracked while they played a tune twice, once while sitting and once while standing. RESULTS: We found moderate correlations between the number of painful joints in the last year and factors, such as physical comfort while playing, years of playing, and position during playing. During standing, lower back pain severity correlated with the rotation range of the torso, while during sitting, it moderately correlated with the average radial-ulnar deviation of the right wrist. During sitting, we found higher anterior and right tilt of the torso, combined with greater abduction of the right shoulder, higher flexion in the left shoulder and higher radial deviation in the left wrist. CONCLUSION: Our results point to several risk factors, related both to playing habits but also to playing posture, which should be considered by the guitar players in order to prevent playing-related musculoskeletal disorders.

Impaired psychomotor vigilance associated with sleep-disordered breathing in women working in the care of older adults in Japan.

PURPOSE: With a rapidly aging society, there is increasing interest in the health of female workers in the field of care services for older adults due to increasing demands to maintain 24-h care and to support older adults without errors or accidents. Therefore, the purpose of this cross-sectional study was to examine the association between sleep-disordered breathing (SDB) and sustained attention in women caring for older adults in Japan. METHODS: The study was conducted in women aged 18-67 years old working in care service facilities for older adults in Japan. The sustained attention of participants was measured by the 10-min psychomotor vigilance task (PVT). SDB was assessed based on the respiratory disturbance index (RDI), which was measured using an ambulatory airflow monitor with a polyvinylidene fluoride (PVDF) film sensor to monitor the respiratory airflow of nasal and oral breathing. The participants wore the monitor to record the breathing status while asleep at home. The severity of SDB was categorized as follows: normal, RDI < 5 events/h; mild SDB, RDI 5-10 events/h; and moderate-to-severe SDB, RDI ≥ 10 events/h. RESULTS: Of 688 women enrolled, medians of age, body mass index (BMI), sleep duration, and prevalence of hypertension tended to be higher with increasing RDI. No significant association was found between RDI and PVT parameters. However, when we limited the analysis to women with BMI ≥ 22 kg/m2, those with moderate-to-severe SDB had significantly higher odds of having the slowest 10% reaction times compared to those without SDB (OR = 2.03; 95% CI = 1.17-3.53). The association did not decrease after adjusting to account for sleep duration, alcohol drinking habits, and history of hypertension (OR = 1.97; 95% CI = 1.10-3.52). A significant increasing trend was also found between RDI and the slowest 10% of reaction times (p for trend = 0.03). CONCLUSIONS: Our findings suggest that SDB is associated with reduced sustained attention in participants with BMI ≥ 22 kg/m2, although the number of assessments of SDB and PVT was only once per participant due to the nature of the cross-sectional study.

Exploring the Underlying Mechanisms of Action of Dry Needling: What Is the Immediate Effect on Muscle Electrophysiology? An Experimental Randomized Controlled Trial.

OBJECTIVE: Dry needling is a commonly used treatment technique for myofascial pain syndromes, such as trapezius myalgia. Despite the shown positive clinical effects on pain, the underlying mechanisms of action, such as the effect on muscle electrophysiology, remain unclear. The aim of this study was to investigate the effect of dry needling, compared with sham needling, in the upper trapezius muscle on surface electromyography activity and the relation with pain in office workers with trapezius myalgia. DESIGN: For this experimental randomized controlled trial, 43 office workers with work-related trapezius myalgia were included. Surface electromyography activity was measured before and after a pain-provoking computer task and immediately after, 15, and 30 mins after treatment with dry or sham needling. Pain scores were evaluated at the same time points as well as 1, 2, and 7 days after treatment. RESULTS: No significant differences in surface electromyography activity between dry needling and sham needling were found. Significant positive low to moderate Spearman correlations were found between surface electromyography activity and pain levels after dry needling treatment. CONCLUSIONS: This study shows no immediate effects of dry needling on the electrophysiology of the upper trapezius muscle, compared with sham needling.

Correlation analysis of cervical spine dysfunction, pain and muscle strength in office workers / 中华劳动卫生职业病杂志

Objective: To expore the correlation between neck disability, neck pain and muscle strength in cervical pondylosis of office worker, and to provide scientific basis for the prevention and treatment of cervical spondylosis. Methods: In April 2021 ,234 patients with cervical spondylotic myelopathy treated in the Subsidiary Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine from April 2015 to April 2017 were selected, the correlation between Neck Disability Index (NDI) score, neck pain and muscle strength was analyzed using the Spearman rank correlation method. Mann-Whitney U test was used to compare the difference of maximum muscle strength of isometric contraction. Results: NDI score was negatively correlated with neck flexion, extension, and muscle strength in the left and right flexion directions (r(s)=-0.164, -0.169, -0.222, -0.176, P=0.012, 0.010, 0.001 , 0.007). In mild and moderate functional disorder patients, the muscle strength in flexion, extension and left and right flexion direction was greater, the difference was statistically significant (P <0.01). Conclusion: There is a negative correlation between cervical functional disorder and cervical muscle strength in office workers, suggesting that strengthening cervical muscle strength may be a way to improve cervical spine function.

Experimental study on the effect of Si and P ion content in SiO2 exposure environment on the degree of pulmonary fibrosis.

BACKGROUND: Silicosis is a public health issue in developing countries for long and cannot be completely cured. OBJECTIVE: To study the changes of ion content with TNF-α and TGF-ß expression in alveolar lavage fluid (BALF) at different time points in rats exposed to silica and to investigate their correlation with pulmonary fibrosis. METHODS: 42 rats were randomly divided into control group (n = 12) and exposure group (n = 30). Tissues of right lower lungs were collected and fixed for further Hematoxylin-eosin (HE) and Masson staining. We collected the BALF to examine the inflammatory cytokines of TNF-α and TGF-ß and measured the ion contents in BALF. RESULTS: The increase of TNF-α level was earlier than TGF-ß. The content of silica in BALF was significantly increased after exposure and reached the maximum at 7th day, similar to the curve of cytokine TGF-ß level. However, phosphorus ions increased quickly after gradual decline of silicon ion and roughly proportional to the curve of degree of fibrosis. CONCLUSIONS: Crystalline silica exposure can cause changes in TGF-ß and TNF-α in BALF and accompanied with fibrosis and ions content variation. The abnormal expression of phosphorus ion may have significance in the occurrence and development of silicosis.

Altered Attention Network in Paratroopers Exposed to Repetitive Subconcussion: Evidence Based on Behavioral and Event-Related Potential Results.

Cognitive impairment caused by repetitive subconcussion has received increasing attention in recent years. Although the dysfunction of attention has been confirmed by neuropsychological research using scales, there is no event-related potentials (ERPs) research. The Attention Network Test (ANT) has been widely used to evaluate the three separate components of attention processing (alerting, orienting, and executive control). Twenty-seven paratroopers exposed to repetitive subconcussion (subconcussion group) and 25 matched healthy control participants (HCs group) were enrolled, and all of them performed the ANT test while continuous scalp electroencephalography data were recorded. On the behavioral performance level, the subconcussion group showed a slower task response, with an especially significant slower reaction time in alerting. Concerning ERP results, reduction amplitudes of cue-N1 in the alerting network were observed, indicating that this group was less able to make efficient use of cues and maintain an alerting state for incoming information. For the orienting network, no difference in N1 amplitude was observed between the two groups. Moreover, there was a reduced P3 amplitude in the executive control network in the subconcussion group compared with the HCs group, suggesting a dysfunction of attentional resource allocation and inhibition control in the former group. This study is, to our knowledge, the first analysis of the altered attention network caused by repetitive subconcussion from the perspectives of behavioral and neuropsychology levels. These preliminary results revealed the possible damage of the alerting and executive control networks and provided a reference for further research on subconcussion cognitive impairment.

Surgeon Positioning During Awake Laryngeal Surgery: An Ergonomic Analysis.

OBJECTIVES: While it is acknowledged that otolaryngologists performing microlaryngeal surgery can develop musculoskeletal symptoms due to suboptimal body positioning relative to the patient, flexible laryngoscopy and awake laryngeal surgeries (ALSs) can also pose ergonomic risk. This prospective study measured the effects of posture during ergonomically good and bad positions during laryngoscopy using ergonomic analysis, skin-surface electromyography (EMG), and self-reported pain ratings. STUDY DESIGN: Prospective cohort study. METHODS: Eight participants trained in laryngoscopy assumed four ergonomically distinct standing positions (side/near, side/far, front/near, front/far) at three different heights (neutral-top of patient's head in line with examiner's shoulder, high-6 inches above neutral, and low-6 inches below neutral) in relation to a simulated patient. Participants' postures were analyzed using the validated Rapid Upper Limb Assessment (RULA, 1 [best] to 7 [worst]) tool for the 12 positions. Participants then simulated ALS for 10 minutes in a bad position (low-side-far) and a good position (neutral-front-near) with 12 EMG sensors positioned on the limbs and torso. RESULTS: The position with the worst RULA score was the side/near/high (7.0), and the best was the front/near/neutral (4.5). EMG measurements revealed significant differences between simulated surgery in the bad and good positions, with bad position eliciting an average of 206% greater EMG root-mean-squared magnitude across all sampled muscles compared to the good posture (paired t-test, df = 7, P < .01), consistent with self-reported fatigue/pain when positioned poorly. CONCLUSION: Quantitative and qualitative measurements demonstrate the impact of surgeon posture during simulated laryngoscopy and suggest ergonomically beneficial posture that should facilitate ALSs. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2752-2758, 2021.

Workplace noise exposure and the prevalence and 10-year incidence of age-related hearing loss.

There is paucity of population-based data on occupational noise exposure and risk of age-related hearing loss. Therefore, we assessed cross-sectional and longitudinal associations of past workplace noise exposure with hearing loss in older adults. At baseline, 1923 participants aged 50+ years with audiological and occupational noise exposure data included for analysis. The pure-tone average of frequencies 0.5, 1.0, 2.0 and 4.0 kHz (PTA0.5-4KHz) >25 dB HL in the better ear, established the presence of hearing loss. Participants reported exposure to workplace noise, and the severity and duration of this exposure. Prior occupational noise exposure was associated with a 2-fold increased odds of moderate-to-severe hearing loss: multivariable-adjusted OR 2.35 (95% CI 1.45-3.79). Exposure to workplace noise for >10 years increased the odds of having any hearing loss (OR 2.39, 95% CI 1.37-4.19) and moderate-to-severe hearing loss (OR 6.80, 95% CI 2.97-15.60). Among participants reporting past workplace noise exposure at baseline the 10-year incidence of hearing loss was 35.5% versus 29.1% in those who had no workplace noise exposure. Workplace noise exposure was associated with a greater risk of incident hearing loss during the 10-year follow-up: multivariable-adjusted OR 1.39 (95% CI 1.13-1.71). Prior occupational noise exposure was not associated with hearing loss progression. Workplace noise exposure increased the risk of incident hearing loss in older adults. Our findings underscore the importance of preventive measures which diminish noise exposure in the workplace, which could potentially contribute towards reducing the burden of hearing loss in later life.

Dynamic brain connectome and high risk of mental problem in clinical nurses.

With the growing population and rapid change in the social environment, nurses in China are suffering from high rates of stress; however, the neural mechanism underlying this occupation related stress is largely unknown. In this study, mental status was determined for 81 nurses and 61 controls using the Symptom Checklist 90 (SCL-90) scale. A subgroup (n = 57) was further scanned by resting-state functional MRI with two sessions. Based on the SCL-90 scale, "somatic complaints" and "diet/sleeping" exhibited the most prominent difference between nurses and controls. This mental health change in nurses was further supported by the spatial independent component analysis on functional MRI data. First, dynamic functional connectome analysis identified two discrete connectivity configurations (States I and II). Controls had more time in the State I than II, while the nurses had more time in the State II than I. Second, nurses showed a similar static network topology as controls, but altered dynamic properties. Third, the symptom-imaging correlation analysis suggested the functional alterations in nurses as potential imaging biomarkers indicating a high risk for "diet/sleeping" problems. In summary, this study emphasized the high risk of mental deficits in nurses and explored the underlying neural mechanism using dynamic brain connectome, which provided valuable information for future psychological intervention.

Occupational Physical Activity and New-Onset Hypertension: A Nationwide Cohort Study in China.

[Figure: see text].

The development and use of an anatomy-based retraining program (MusAARP) to assess and treat focal hand dystonia in musicians-A pilot study.

BACKGROUND: Movement dysfunctions are commonly reported in musicians, and in extreme cases may result in a persisting loss of motor control. This condition, whereby motor control of the hand during previously highly trained movements on the instrument is lost, is termed focal hand dystonia. It is widely considered to be a consequence of prolonged repetitive daily practice, often in combination with exposure to a range of other risk factors. Current literature recommends retraining as a promising treatment intervention, although only scant scientific evidence exists on which components should be included in a retraining program, and how these may be best administered. METHODS: A progressive muscle activation and movement exercise program was devised by one of the authors applying a series of anatomy-based off-instrument movement tasks. This series of fine motor control exercises, was used to both assess and retrain focal hand dystonia in a population of musicians. The standardized approach aimed to provide a systematic method of retraining musically relevant muscular synergies that could later be applied to the instrument, while still allowing individual modifications. Retraining sessions were mostly run online as a consequence of the coronavirus pandemic, although some early sessions were also able to be undertaken face to face. Both qualitative and quantitative measures were used in this case series to evaluate program efficacy, due to the typical heterogeneity of the focal hand dystonia participants. This included: blinded external neurological evaluation of video footage using the Tubiana grading system, written subjective feedback, exercise progressions, and performance outcomes. RESULTS: Pilot testing of 4 patients indicated the utility of the program over approximately a 12- month time period. All subjects improved, 2 of whom have returned to pre-dystonia performance levels. These patients reported the importance of patience and persistence with daily exercise sessions in their recovery. CONCLUSION: Using off-instrument playing-relevant exercises to enhance fine motor control and muscle activation can be effective in retraining focal hand dystonia, regardless of additional treatments or level of performance. They should be regularly practiced and progressed in order for effects to be best progressed to instrumental applications. Further research may elucidate whether there are optimal outcomes with single or particular combinations of treatment approaches.

The influences of the environment and information on the complications of diabetes on patient outcomes.

This letter was written to address two concerns about the results of the paper published by Zeynep et al. (BMC Health Qual Life Outcomes 18:265, 2020). First, the differences between the two groups in the environment with or without occupation may strengthen the primary outcome results. Second, lack of information on the complications and treatments of diabetes makes interpretation of the results difficult.

Attenuated cardiovascular reactivity is related to higher anxiety and fatigue symptoms in truck drivers.

Depression and anxiety have been linked with reduced stress-induced cardiovascular reactivity (CVR), which could be indicative of autonomic dysregulation. Less is known about the association between work-related fatigue and CVR. Truck drivers experience high levels of depression, anxiety, and fatigue, with repeated psychophysiological stressors on the road, yet little is known about the effects of these conditions on their CVR. Three hundred eighty six truck drivers completed the Hospital Anxiety and Depression Scale (HADS) and the Occupational Fatigue Exhaustion/Recovery Scale (OFER-15). Systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) were measured at rest and during a stressor protocol to measure CVR. Multivariate regression analyses were used to determine relationships between variables and adjusted for nine key covariates. Higher symptoms of persistent fatigue were related to a reduced SBP reactivity (ß = -.236, p = .009) and reduced DBP reactivity (ß = -.257, p = .005), whereas there was a positive trend between acute fatigue and DBP reactivity (ß = .169, p = .052). Higher symptoms of anxiety were related to a reduced SBP reactivity (ß = -.164, p = .016). This study demonstrated in a population of truck drivers that both anxiety and persistent fatigue were related to an attenuated SBP reactivity in a combined model, whereas there was a positive trend between acute fatigue solely and DBP reactivity. These novel findings may have serious implications for cardiovascular disease risk in truck drivers, and future research should attempt to establish the causal effect of these associations and the underlying physiological mechanisms.

Correlation between real-time heart rate and fatigue in chest compression providers during cardiopulmonary resuscitation: A simulation-based interventional study.

BACKGROUND: The American Heart Association guidelines recommend switching chest compression providers at least every 2 min depending on their fatigue during cardiopulmonary resuscitation (CPR). Although the provider's heart rate is widely used as an objective indicator for detecting fatigue, the accuracy of this measure is debatable. OBJECTIVES: This study was designed to determine whether real-time heart rate is a measure of fatigue in compression providers. STUDY DESIGN: A simulation-based prospective interventional study including 110 participants. METHODS: Participants performed chest compressions in pairs for four cycles using advanced cardiovascular life support simulation. Each participant's heart rate was measured using wearable healthcare devices, and qualitative variables regarding individual compressions were obtained from computerized devices. The primary outcome was correct depth of chest compressions. The main exposure was the change in heart rate, defined as the difference between the participant's heart rate during individual compressions and that before the simulation was initiated. RESULTS: With a constant compression duration for one cycle, the overall accuracy of compression depth significantly decreased with increasing heart rate. Female participants displayed significantly decreased accuracy of compression depth with increasing heart rate (odds ratio [OR]: 0.97; 95% confidence interval [CI]: 0.95-0.98; P < .001). Conversely, male participants displayed significantly improved accuracy with increasing heart rate (OR: 1.03; 95% CI: 1.02-1.04; P < .001). CONCLUSION: Increasing heart rate could reflect fatigue in providers performing chest compressions with a constant duration for one cycle. Thus, provider rotation should be considered according to objectively measured fatigue during CPR.

Chronic productive cough and inhalant occupational exposure-a study of the general population.

PURPOSE: Occupational inhalant exposures have been linked with a higher occurrence of chronic productive cough, but recent studies question the association. METHODS: We included participants from two general population studies, the Copenhagen City General Population Study and the Copenhagen City Heart Study, to assess contemporary (year 2003-2017) and historical (1976-1983) occupational inhalant hazards. Job titles one year prior to study inclusion and an airborne chemical job-exposure matrix (ACE JEM) were used to estimate occupational exposure. The association between occupational exposures and self-reported chronic productive cough was studied using generalized estimating equations stratified by smoking status and cohort. RESULTS: The population consisted of 5210 working individuals aged 20-65 from 1976 to 1983 and 64,279 from 2003 to 2017. In smokers, exposure to high levels of mineral dust, biological dust, gases & fumes and the composite variable vapours, gases, dusts or fumes (VGDF) were associated with chronic productive cough in both cohorts with odds ratios in the range of 1.2 (95% confidence interval, 1.0;1.4) to 1.6 (1.2;2.1). High levels of biological dust were only associated with an increased risk of a chronic productive cough in the 2003-2017 cohort (OR 1.5 (1.1;2.0)). In non-smokers, high levels of VGDF (OR 1.5 (1.0;2.3)) and low levels of mineral dust (OR 1.7 (1.1;2.4)) were associated with chronic productive cough in the 1976-1983 cohort, while no associations were seen in non-smokers in the 2003-2017 cohort. CONCLUSION: Occupational inhalant exposure remains associated with a modestly increased risk of a chronic productive cough in smokers, despite declining exposure levels during the past four decades.

Efficacy of Deep Cervical Flexor Muscle Training on Neck Pain, Functional Disability, and Muscle Endurance in School Teachers: A Clinical Trial.

BACKGROUND: Neck pain (NP) is a common work-related disorder, with high prevalence in the profession of teaching. The daily duties of a school teacher involve head-down postures while reading and writing, which expose them to the risk of developing NP. Deep cervical flexor (DCF) muscles have been reported to have lower endurance in patients with cervical impairment, which has additionally been associated with disability. There is limited evidence regarding the efficacy of training of DCF muscles in occupational NP. The objective of this study was to investigate the effects of DCF muscle training on pain, muscle endurance, and functional disability using pressure biofeedback in school teachers with NP. METHODS: Sixty-five teachers (age, 25-45 years) with more than 5 years of teaching experience participated in this study. They were randomly divided into two groups: the experimental (E) and control (C) groups. In the E group, the subjects underwent DCF muscle training using pressure biofeedback in addition to conventional exercises for neck pain, while those in the C group underwent conventional exercises only. Pain, muscle endurance, and disability were measured at day 0 (before the treatment) and days 14 and 42 after the treatment. Endurance of DCF muscles was measured by the craniocervical flexion test using pressure biofeedback, pain intensity was measured using the numeric pain rating scale, and functional disability was assessed using the neck disability index questionnaire. This study was performed in accordance with CONSORT guidelines. RESULTS: On day 0, there were no significant differences in the age, pain, muscle endurance, and disability levels between the groups. After initiating the intervention, although there were improvements in both groups, there was a statistically significant improvement in muscle endurance, pain, and disability in subjects who received additional training with pressure biofeedback. CONCLUSIONS: Besides increasing muscle endurance, specific training of DCF muscles in addition to conventional exercises can improve neck pain and functional disability. These results should be further correlated clinically. A dedicated time for exercises at school could help prevent the development of NP in teachers. This trial is registered with ClinicalTrials.gov NCT03537300 May 24, 2018 (retrospectively registered).

SiO2 stimulates macrophage stress to induce the transformation of lung fibroblasts into myofibroblasts and its relationship with the sphingomyelin metabolic pathway.

Silicosis is a serious occupational disease with the highest incidence in China. However, its pathogenesis has not been fully elucidated. Studies have shown that the sphingomyelin signaling pathway may play an important role in different fibrotic diseases but its role in silicosis-mediated fibrosis is still unclear. In this study, the supernatant of human peripheral blood mononuclear cell line (THP-1)-derived macrophages exposed to silica (SiO2 ) was used to stimulate the transformation of human embryonic lung fibroblast cell line (HFL-1) into myofibroblasts, and the intervention effect of recombinant human acid ceramidase (rAC) was observed. The results showed that SiO2 stimulated the production of reactive oxygen species and malondialdehyde in the supernatant of THP-1-derived macrophages and increased the secretion of TGF-ß1, TNF-α, and IL-8. In addition, we found that the expression levels of α-SMA, FN, Col I, and Col III in HFL-1 cells increased. Meanwhile, the activities of ASMase and ACase and the expression levels of Cer, Sph, and S1P were increased. Intervention by rAC can suppress these changes to different degrees. In conclusion, the present study shows that SiO2 dust poisoning may stimulate HFL-1 cell differentiation into myofibroblasts by inducing oxidative stress in THP-1-derived macrophages, thereby promoting the secretion of a variety of inflammatory factors and activating the sphingolipid signaling pathway in HFL-1 cells. Exogenous rAC can effectively interfere with the stimulation of HFL-1 cells by silica in vitro.